This invention relates to layer-silicate products for example vermiculite products, and in particular to a method of imparting water resistance thereto.
It is known that the mineral vermiculite (and other layer-silicate minerals containing vermiculite layers, for example hydrobiotite or chlorite-vermiculite) may be fabricated into articles, for example, film, sheets or foam. Methods for the production of such materials are described in UK Pat. Nos. 1,016,385, 1,076,786 and 1,119,305, and copending UK application Nos. 51425/76 and 39510/76. Other layer-silicate minerals also form films or sheets, for example those described in U.S. Pat. No. 2,266,636. All the fabricated articles suffer from the disadvantage that they are affected by water, for instance unless they are protected e.g. by hydrophobic coatings, water will soak in and swell the mineral rendering it rather weak. Prolonged soaking in water may result in disintegration of the fabricated article.
However we have now found that a treatment may be given to the fabricated article which will stabilise it against disintegration in water.